One-step synthesis of macromonomers catalyzed by phosphazene base

Herein, we report one-step synthesis of polymethacrylates-based macromonomers (MMs) in the presence of an organocatalyst phosphazene base ( t -BuP 4 ) and a functional initiator N -butyl-4-vinylbenzamide ( N -BVBA) containing a secondary amide and a styrenic double bond. A series of styrenic MMs with controlled molecular weight and relatively narrow polydispersity were synthesized under mild conditions. Detailed NMR analyses of the initiation process suggested that the anionic polymerization was initiated by nitrogen anion generated from abstraction of the proton from the secondary amide. NMR and MALDI-TOF MS analyses confirmed: (1) the selective polymerization of methacrylate-type double bonds, (2) controlled chain-end functionality of MMs with an unreacted styrenic double bond, as well as (3) the absence of transesterification between N -BVBA and methacrylate monomers. Furthermore, the homopolymerization and copolymerization of the MMs with comonomers were carried out for the preparation of graft copolymers. Through conventional radical polymerization, graft copolymers with different grafting densities were obtained at high MMs conversions, indicating the high reactivity of MMs. Thus, the one-step approach demonstrates a simple metal-free access to the controlled synthesis of MMs, and the prepared MMs can polymerize efficiently to convert into graft copolymers. Graphical Polymethacrylates-based macromonomer with a reactive styrenic double bond at the polymer chain-end was successfully synthesized by a one-step polymerization of methacrylates initiated by N -butyl-4-vinylbenzamide in the presence of t -BuP 4 as the organocatalyst. The macromonomers featured with controlled molecular weights and high fidelity chain-ends are highly reactive in the conventional radical polymerization to prepare graft copolymers with variable grafting densities.